Centrifugal pump



P. K. GIRTON CENTRIFUGAL PUMP Nov. 5, 1963 2 Sheets-Sheet 1 Filed 001;.26, 1960 m m m m Nov. 5, 1963 P. K. GIRTON CENTRIFUGAL PUMP 2Sheets-Sheet 2 Filed Oct. 26, 1960 ll l H.) I x4965 8 66' Will L- l-iL-J W I: i

INVENTOR. Wigwam BY 3U EMEEW United States Patent 3,109,330 CENTREFUGALPaul K. Girton, lvliillville, Pa, assignor to Girton l duuu-= fact-usingfiompany, inn, lviillville, Pa, a corporation of Pennsylvania Filed Get.25, we'd}, Serdl io. mass 19 (Claims. (til. rea -av This inventionpertains to improvements in centrifugal pumps. More specifically statedthis invention relates to improvements in centrifugal pumps of thecompact type provided with fixed impellers and provided with automaticfeathering or automatic adjusting impellers.

This invention also pertains to sanitary improvements in the housing andin the operative elements of the improved pump, whereby to incorporatein the pump such construction and arrangement of parts as to render theimproved puimp easy to maintain in sanitary condition and to enable theeasy and rapid assembly, disassembly, inspection and cleaning of thepump.

This invention also pertains to improvements in the arrangement fordemountably supporting the sections of the housing of the improved pump,whereby to enable the easy and quick dismantling of the pump from itssupport and whereby to utilize the support for accurately andindependently positioning the sections of the pump housing with respectto one another and with respect to the drive mechanism of the pump.

The aspect of this invention pertaining to improvements in pump housingsis claimed in the copending divisional application entitled PumpHousing, filed March 7, 1961, Serial No. 94,049, now Patent No.3,033,121.

Centrifugal pumps of the type contemplated by this invention arefrequently used in the handling of readily perishable food products,necessitating the frequent disassembly, cleaning and reassembly of thepump. In food processing establishments and in similar establishments,pumps of the type contemplated by this invention are frequently shiftedfrom one flow system to another flow system, requiring easy adjustmentof the position of the discharge connection of such pumps. In such flowsystems the rate of flow of the product is frequently controlled byadjustments of valves on the discharge side of the pump. In the eventsuch adjustments are made rapidly to reduce the volume of flow ofproduct, overloading of the pump motor frequently occurs with theresulting damage to the driving motor.

It is therefore an object of this invention to provide a relativelysimple centrifugal pump including a compound impeller mechanism havingboth fixed impeller elements and automatically feathering orcompensating impeller elements.

A further object of this invention is to provide a compound impellermechanism for a centrifgual pump which may be readily assembled into andalso disassembled as a unit from the pumping chamber and wherein theautomatically compensating or feathering impelling elements may beeasily assembled onto or disassembled from the fixed or rigid impellerelements without the use of tools and without the use of any movableseparate parts and wherein the automatically adjustable impellerelements are locked in operative position within the pump housing fromwhich they may not become accidentally displaced when the pump unit isassembled in operative arrangement.

A still further object of this invention is to provide an improved pumpmechanism embodying the foregoing features wherein all of the surfacesof the disassembled operative parts of the improved pump may be easilyinspected without the use of any tools and may be easily cleaned.

Another object of this invention is to provide an improved sectionalpump housing and an improved support for adjustably supporting such pumphousing wherein the 3*, l 9938b Patented Nov. 5, 1963 sections of thepump housing are independently supported and automatically centered andaligned with the impeller mechanism and wherein the sections of theimproved housing are sealed one to another by an improved seal arrangernent, whereby to automatically preclude the failure of such sealirrespective of the operation of the improved pump undersupcratmospheric pressure or under subatrnospheric pressure, and whereinthe rotary seal through which the drive shaft enters the pump housingthrough an aperture in an end face of the housing is protected duringthe operation of the pump from the direct action of the pressure withinthe housing by the overlapping arrangement between the shaft seal andthe rigid portion of the fixed impeller mechanism.

Another object of this invention is to provide an improved pump having acompound impeller consisting of a rotatable rigid, fixed impel-lingsurface, impeller element carrying automatically compensating orfeathering coacting impeller elements, which feathering-type impellingelements are automatically adjusted to maximum impellin'g positionsolely by centrifugal force and which are automatically adjusted toreduced imp-oiling position responsive to increases in the dischargepressure or increases in the viscosity of the material being pumped.

A further object of this invention is to provide a simple andinexpensive component for releasably locking the impelling element tothe drive shaft of the pump by an arrangement which may easily andquickly be assembled and disassembled and cleaned.

An improved pump embodying the various new, novel and useful features ofthis invention, whereby to attain the foregoin objectives, possesses theadvantages of compactness, simplicitiy of construction, ease andrapidity of assembly and disassembly, ease of cleaning and inspection,independent support and automatic alignment and centering of thesections of the pump housing and the impeller mechanism, readyadjustable discharge connection, rupture proof housing seal and pressureprotected drive shaft seal, automatic avoidance of overload of thedriving motor, ready separable impeller sections which may be. assembledand disassembled without the use of tools and which are locked inoperative assembly by the pump housing, and automatic feathering ofsections of the compound impeller element whereby the adjustableimpelling elements are expanded to maximum capacity responsive to theirown cenrtifugal force and are depressed or contracted to mini mumoperative position responsive to increases in viscosity or dischargepressure of the fluid being pumped.

The foregoing and other objectives, important new, novel and usefulfeatures and advantages of this invention will become more apparent andbe more easily understood upon examination of the following descriptionthereof and the accompanying drawings and appended claims. it should,however, be remembered that, WllhOllt desire of limitation, theinvention will be described and illustrated as the preferred embodimentof the invention in a centrifugal pump. Certain changes and variationsin the invention may, upon review of this application, suggest them:

selves to those skilled in the pertinent arts, which changes may,however, not depart from the spirit of this invention and may comewithin the scope of the appended claims.

in the accompanying drawings:

FIGURE 1 is a side elevational View, partially in broken away verticalsection, of the improved centrifugal pump embodying the presentinvention;

FIGURE 2 is a left hand or front elevational view of the improved pumpas shown in FIGURE 1, partially in broken away section, showing theautomatically adjustable impeller vanes in expanded operative positionand also schematically illustrating a depressed position of theutomatically adjustable impeller vanes;

FIGURE 3 is a plan view of the impeller subassembly;

FIGURE 4 is a side elevational View, partially in broken away verticalsection, of the impeller subassem-bly shown in FIGURE 3;

FIGURE 5 is a plan view of one of the automatically adjustable impellervanes;

FIGURE 6 is an enlarged vertical fragmentary view, partially in section,showing the interrelation of the edge portions of the front pump headand the rear pump head and the casing seal and the casing support frameat the locus of coaction of those elements;

FIGURE 7 is a side view of the rear head of the housing of the improvedpump showing the resilient seal for the housing sections in transversesection; and

FIGURE 8 is an elevational view illustrating the arrangement fordrivingly connecting and locking the hub of the improved impellermechanism to the drive shaft.

Referring to the drawings, in which like elements are identified by likenumerals, 11} represents a driving unit, such as an electrical motor,enclosed in a housing and having a central rotary power shaft 11extending from one end thereof and mounted in suitable bearings (notshown) adapted to support the shaft 11 against radial and axial thrust.Shaft coupling 12 is coaxially and drivingly mounted on shaft 11 intelescopic arrangement and is provided with an oil guard ring 13 on itsend adjacent drive 10. Coupling 12 drivingly carries a pump drive shaft14, coaxially arranged with the motor shaft 11 for rotation by shaft 11A cylindrical support frame or element 15, for supporting a pump housingis coaxially mounted in fixed position on the end of the driving unit11) and surrounds the shaft 111 and the coupling 12 and the inner end ofthe pump shaft 14. The end of the frame or support farthest removed fromthe motor 110 is in a plane perpendicular to the axis of pump shaft 14and that end of the substantially cylindrical frame 15 is provided witha cylindrical inner face 16 coaxially arranged with respect to pumpshaft 14. An annular flange 17 extends inwardly from face 16 and isprovided with a flat face 18 perpendicular to the cylindrical face 16and the axis of shaft 14. Face 18 together with face 16 forms anoutwardly or forwardly opening right angle groove 19 having concentricannular faces 16 and 13.

A sectional pump casing or housing is supported on the free end of frame15 and is formed of front housing section 20 which is substantiallycup-shaped and generally cylindrical and is formed of a substantiallyflat and centrally apertured front head portion 21 and a substantiallycylindrical side wall portion 22 which is perpendicular to front headportion 21 Side wall 22 is provided with a substantially tangentialdischarge connection 23. Side wall 22 is coaxial with frame 15 and shaft14- and has an outer diameter slightly less than the inner diameter offace 16 of groove 19 whereby to permit the relatively snug teleing theinner edge of the central and circular aperture 25 in front head 26. Asthus supported, front housing section 20 may be rotated within frame 15about the axis of shaft 14 so as to dispose the outlet connection 23 atany desired angle.

Rear housing section or rear pump head 26 comprises a substantially flatand circular disc having parallel front and rear side surfaces 27 and 28respectively and having a central circular aperture 29 telescoped overand coaxial with pump shaft 14-. The rear pump head 26 is supportedperpendicular to pump shaft 14 and is parallel to front pump head 21 andis parallel to face 18 of groove 19'. The cylindrical outer edge surface30 of rear head 26 defines the outer edge of rear face 23 of head 26 andis coaxial with and of a diameter slightly less than the cylindricalface 16 of groove 19 into which the rear head 26 is telescopicallyseated inwardly of the side wall 22 of housing section is with the edgesurface 36 in coaxial and centering engagement with face 16 and with theouter portions of the circular rear face 28 of head 26 parallel to andin mating or abutting engagement with the complementary surface 15% ofgroove 19;

The circular inner or front surface 27 of rear casing head 26 is definedat its outer periphery by a cylindrical edge surface 31. The paralleland axially spaced cylindrical edge surfaces 39 and 31 are coaxial withshaft 14 and are positioned intermediate the parallel planes of thesurfaces 27 and 28 of the rear head 26. Edge surface 36 is of greaterdiameter than edge surface 31 and the adjacent edges of surfaces 31 and3 1 are joined by a circular and uniformly curved groove or seal seat32, the inner portion of which groove 32 is defined by a re-entrantcircular surface 33 which is coaxial with groove face '16 and which atits upper edge joins the surface 31 and extends generally rearwardlyfrom surface to an annular and flat surface 34 which is parallel to therear face 28 and extends inwardly from the coaxial cylindrical surface36 to join in the lower edge of the re-entrant surface 33.

The annular surface 34 of rear head 26 is parallel to and abuts againsta complementary and parallel annular fiat edge surface 35 which definesthe radially outer portion of the inner end of side wall 22 of the frontpump head 21). The inner end of the outer cylindrical surface 36 of sidewall 22 terminates in the outer edge of surface 35. The inner edge ofthe annular surface 35 is joined, by an inwardly diverging or beveledand annular surface 37 concentric with surface 16, with the innerterminal end of the inner cylindrical surface 38 of side Wall 22.

The front housing section 213 and the complementary and interfitted rearhousing section 26 being thus concentrically and independently supportedradially in groove 19 and being thus coactively supported against axialdisplacement by flange 17, the outer peripheral portions of the housingsections 20 and 26 are sealed one to another by an annular and resilientseal ring 39, of circular cross section, snugly fitted sealingengagement with and seated in the groove or seal seat 32 of the rearpump head 26. The circular radial cross section of seal ring 39 issulficiently great that the outer surface of the seal ring 39 sealinglyengages the beveled surface 37 of the end of the inner side of the sidewall 22. Due to the re-entrant curvature of groove wall 3 3, anypressure within the pump chamber will tend to force the seal gasket 39into a more compressed and more tightly engaging or sealing position.The thus supported and sealed pump housing sections 20 and 26 are lockedin such operative position on frame 15 by a circular compression yoke41} which surrounds the inlet connection 24 and compressively engagesthe outer front surface of the front housing section 21 Yoke 40 isprovided with two oppositely positioned and bifurcated peripheral lugs41, receiving tension bolts 42 hingedly supported by hinge pins 43 onsimilar positioned lugs 44 formed on the outer surface of the frame 15.Compression nuts '45 threaded onto the free ends of bolts 42, whentightened into compressive engagement with lugs 41, produce acompressive biasing of yoke 40 toward frame :15, thereby locking thesections 20 and 26 of the housing in sealed and rigidly supportedarrangement in groove 19 of frame 15, and coaxially arranged with pumpshaft 14.

The aperture 29 in rear housing section 26 is sealed by a rotary sealcomprised of an antifriction annular seal element 46 telescoped overpump shaft 14 and slidingly and sealingly engaging the rear surface 28of housing section 2-6. Seal element 46 is sealed to drive shaft 14 bygasket element 47 sealingly fitted into seal ring 46 and sealinglyengaging the outer periphery of shaft 14. Seal ring 46 is maintained insealing engagement by the compressed coil spring 48 telescoped overshaft 14 intermediate coupling collar 12 and seal ring 46, which twoelements are compressively engaged by the opposite ends of thecompressed spring 4 8.

The compound pump impeller subassembly 49, housed within the pumpchamber formed of housing sections 20 and 26, includes an elongated,flat and substantially rectangular and centrally apertured and rigid androtatable impeller element or blade 50, having straight and parallelside edge surface 51 and 52 and having curved ends 53 and 54. The curvedends 53 and 54 are both of the same radius and are parallel to and arespaced slightly inwardly from the inner cylindrical surface 38 of thehousing side wall 22. Impeller element 50 also has parallel front andrear flat faces 55 and 56 respectively. Faces 55 and 56 of impellerelement 50 are perpendicular to the side edge surfaces 51 and 52 and arealso parallel to the front and rear pump housing heads 21 and 26.Impeller element or blade 56 is positioned within the pump housing sothat the rear face 56 of impeller element 50 is positioned very close tothe parallel front surface or face 27 of rear purnp head 26, and so thatthe front face 55 of the impeller element St} is positioned asubstantial distance from the front pump head 21.

A central cylindrical hub 57 is permanently fixed at one end thereof inthe central aperture in impeller element or blade 50, thereby dividingblade 50 into two oppositely directed rigid impeller arms. Hub 57 iscoaxially telescoped over the free end of pump drive shaft 14 andextends from blade 50 coaxially into the pump inlet connection 24. A keyor driving pin 53 extends through aligned apertures in hub 57 and shaft14 to releasably lock impeller element 50 onto shaft 14 against axialmotion and to drivingly connect impeller element 50 for rotation withshaft 14.

Cylindrical and parallel pivot pins 59 extend perpendicularly from face55 of impeller element or blade 50 toward the front pump head 21 andhave their respective central axis positioned on the longitudinal centerline of blade 56 with the respective central axis of the pivots 59spaced radially from the axis of shaft 14 by a distance slightly lessthan the inner radius of the housing inlet 24. Each pivot 59 is providedwith an annular, peripheral groove 60 which is parallel to the adjacentflat forward face 55 of the rigid impeller blade 56, and is alsoprovided with a straight, peripheral, longitudinally extending groove 61which is parallel to the central axis of the respective pivot 59 andextends from the forward end of that respective pivot 59 rearwardly intothe associated annular groove 69. Groove '61 is located in thesemicircular surface segment of pivot pin 59 farthest removed from hub57 and is of the same radial depth as groove 66.

Each of the pivots 59 is provided with or pivotally carries an automaticfeathering or automatic adjusting, rigid, impeller vane element 62 whichis hingedly or pivotally mounted upon the pivot 59. In the operation ofthe improved pump, when operating at maximum pumping efficiency, vanes59 have their free ends extended radially outwardly from the axis ofshaft 14 and from the path of orbiting of the pivots Such outwardextension of the hinged impeller vanes 62 upon the rotation of impellerelement 5% results from the centrifugal force developed within therespective vanes 62 whose respective center of gravity is alwayspositioned or located laterally or to the side of a straight lineextending from the axis of shaft 14- to the axis of the associated pivot59 upon which the vane in question is pivotally mounted.

In operation, the direction of rotation of the fixed impeller blade orpivoted impeller carrying element 50, and the direction of orbiting ofthe hinged impeller vanes 62 carried thereby, is clockwise as viewed inFIGURES 2. and 3. Each impeller vane 62 consists of a substantiallycylindrical and hollow pivot hub section 63 of substantially the samelength as the associated pivot 59 and is telescoped in axial alignmentover that pivot 59 with the flat forward end 64 of hub section 63aligned with the flat forward end of the associated pivot 59. As viewedin FIGURES 2 and 3, pivot hub 63 is provided with a rigid vane element65 which is rigidly fixed tohub section 63 and which, under maximumeffective pumping conditions, extends radially outwardly from shaft 14and pivot 59. Each vane portion 65 is of a width substantially equal tothe width of the pivot hub 63, which width is slightly less than thedistance between the impeller element 50 and the adjacent surface of thefront pump head 21. Each vane portion 65 is perpendicular to the face 55of impeller element 50 and is of a length so that the outer end thereof,when the vane 62 is pivoted to its position of maximum radial extensionon pivot 59, will extend substantially as close to the cylindricalsurface 38 of easing wall 22 as do the ends 53 and. 54 of impellerelement 50. The outer end 66 of impeller vane portion 65 is straight andis parallel to the axis of shaft 14 and the forward and rear edges 67and 68 respectively of vane portion 65 are flat and parallel one toanother and parallel to the front housing section 2.1 and the rearhousing section 26 and the impeller element 56, and edges 67 and 68 arespaced one from another a distance slightly less than the distancebetween the front pump head 21 and the impeller element 56.

As viewed in FIGURES 2 and 3, the hinged impeller vane elements orportions 65 are curved and extend outwardly from their respective pivots59 and also extend rearwardly with respect to the path and direction oforbiting thereof. Each vane portion 65 is provided with a radiallyconvex leading surface 69 parallel to a radially concave trailingsurface 70 as viewed in a plane parallel to the plane of orbiting ofelements 65. The convex surface 69 and the concave surface 76 are bothperpendicular to the flat front face 55 of impeller and impeller carrierelement 56.

To pivotally lock the hinged impeller element 62 on its pivot 59, thereis provided an inwardly extending key 71 anchored in pivot hub 63. Key71 has its inner end extending into groove 68, thus permitting the freepivoting of the hinged impeller section 62 upon pivot 59 until either ofthe sides 69 of 76 of vane 65 engage hub 57 to limit the pivotal motionof impeller section 62. T 0 remove vane 62 from pivot 59, after impellersubassembly :9 has been removed it is only necessary to rotate vane 62clockwise on pivot 59, as viewed in FIGURE 3, until key 71 is alignedwith groove 61, whereupon hub 63 may be lifted from pivot 59. Suchalignment of the inner end of key 71 and groove 61 is attainable, due tothe particular positioning of groove 61 on pivot 59, only when theimpeller vane 62 is pivoted from a position of maximum radial extensionforwardly with respect to its direction of orbiting during operationuntil the convex surface of the vane portion 65 is relatively close tothe hub 57. Due to the combined effects of the before mentionedcurvature of vane portion 65 and the centrifugal force developed byimpeller 62 during operation, such forward pivoting of vane portion 65from a position of maximum extension to a position of alignment of key71 and groove 61, could not take place. The normal hinging action ofimpeller 62, during operation of the pump, is in the opposite directionand such pivoting in such opposite direction cannot be sufficient tobring key 71 into alignment with groove 61.

it will be apparent that when the pump is assembled, vane 62 may not heaccidentally dislodged from pivot 59 in the event of the possiblealignment of key 71 and groove 61 while the pump is at rest, for thereason that the radially outer portion of hub 63 extends radiallyoutwardly a distance greater than the inner periphery of the aperture 25of the front housing head 21 and for the reason that the spacing of thefront end of pivot 59 from front housing head 21 is substantially lessthan would be required to permit the removal of hub 63 from pivot 59.

To insure the readily releasable retention of drive pin 58 in drivingengagement with the hub '57 and shaft 14, through which parts pin 58extends through aligned apertures, a spring or resilient ring 72,consisting of multiple,

closely spaced, turns or coils portions,'is telescoped over hub 57 andlaced through a transverse aperture in one end of drive pin 58. Theinner diameter of spring ring 72 is only slightly greater than theouter'diameter of hub 57 and is less than the distance from the aperturein drive pin 58 to the opposite end of drive pin 58. As assembled inoperative position, the spring ring 72 passes intermediate the free endof pin 58, which extends out of one side of hub 57,and the impellerelement 56. As thus assembled, the inner diameter of spring ring '72 andthe length of drive pin 58 are such as to preclude the movement of ring72 outwardly of the free end of drive pin 58 in any position ofadjustment of pin 58.

The improved pump may be readily disassembled b-y loosening nuts 45,swinging compression bolts 42 outwardly to clear lugs 41, removing yoke4i), removing front housing section '26 from frame 15, unlacingresilient spring ring 72 from driving pin 58, removing pin 58 from hub57 and shaft 14, removing impeller subassembly 49 from shaft 14, andthen removing the rear pump head 26 from frame 15. Seal 46 and spring 4dmay then be removed from shaft 14. The impeller subassembly 4? may bedisassembled as hereinbefore described. Assembly of the improved pumpmay be accomplished by the performance, in opposite order, of thedescribed disassembly steps.

The relative dimensions, construction and arrangement of the hingedimpeller vanes 62 and the dimensions and positioning of the hub 57 andpivots 59 are such as to insure that the center of gravity of the hingedimpeller vanes 62 is always so positioned that upon the rotation ofimpeller subassernbly 49 the vanes 62 will be radially extended solelyby centrifugal force With respect to the position of shaft 14 and pivots59.

In operation the leading convex impelling surface 69 of each of therigid hinged impellers 62, and the leading or fixed impelling surfaceportions of the edge surfaces 51 and 52 of the rigid impeller elementft, urge the pumped fluid received from inlet 24 outwardly against thehousing wall segment 22 for discharge through outlet 23. At maximumpumping efficiency the hinged impeller elements are extendedsubstantially as shown in full lines in FIGURE 2; Any increase indischarge pressure, as may result from sudden closing of a valve in thedischarge line, or increase in the viscosity of the pumped fluid, willcause a responsive proportionate collapse or rearward depression of thehinged impeller elements 62 toward a partially collapsed or depressedposition such as is schematically illustrated by the dot and dashrepresentation of hinged vane segments 65 of FIGURE 2. In theillustrated embodiment of the improved compound impeller, the fixedimpelling surface portions of the surfaces 51 and 52 of the rigidimpeller element 5%} are equal to at least twenty-five percent ofthetotal impelling surface of the improved pump, which total alsoincludes the impelling surfaces of the hinged vanes 62, therebyproviding an improved pump of great flexibility in operating conditionstogether with maximum protection against overloading the driving motor.

From the foregoingdescription of this invention and from theaccompanying drawings, it will be apparent that this invention realizesthe introductorily enumerated objectives respecting the improved pump.It will similarly be apparent that the invention possesses thehereinbefore listed advantages and provides new, novel and usefulimprovements in a centrifugal pump.

Having thus described and illustrated the preferred embodiments of thisinvention, the invention is not to be interpreted as being restricted tothe specifically illustrated and described embodiments, as set forth inthe drawings and as hereinbefore described, except insofar 8 housingmeans having spaced and parallel and substantially flat front and rearhead portions and substantially cylindrical sidewall means definingtogether a pumping chamber, a circular inlet aperture in the center ofthe front head portion of said housing means, a drive shaft aperture inthe center of the rear head portion of said housing means, a rotatabledrive shaft extending through said drive shaft aperture into saidpumping chamber, seal means sealing said drive shaft aperture about saiddrive shaft, an elongated and substantially rectangular and rotatableand rigid impeller element carried centrally thereof by said drive shaftwithin said pumping chamber and having opposed rigid impeller arm meansextending radially outwardly from the axis of rotation of said driveshaft and including integrally formed impelling surface means extendingradially outwardly from the central portion of said impeller element andbeing formed on the leading edges of said impelling arm means andextending substantially axially of said'cylindrical side Wall means anddisposed for rotation in a plane parallel to the plane of the rear headportion of said housing means, said rigid impeller element beingpositioned adjacent the rear head of said housing means and completelyoverlying said seal means, said rigid impeller arm means having amaximum radial dimension greater than the maximum dimension of saidrigid impeller arm means taken perpendicular to the line of maximumradial dimension and having parallel and fiat major front and rearsurfaces parallel to and spaced from the front and rear head portions ofsaid housing means, said impelling surface means being positionedintermediate and joining said flat major front and rear surfaces of saidrigid impeller arm means, pivot means carried by said rigid impeller armmeans intermediate said rigid impeller arm means and the head portion ofsaid housing having the circular inlet aperture, the axis of said pivotmeans being parallel to the axis of said drive shaft and being spacedradially outwardly from said drive shaft a distance substantially equalto the radius of said inlet aperture, and impeller vane means pivotallysupported upon said pivot means for rotation in an orbit about saiddrive shaft in a path parallel to and adjacent to the path of rotationof said rigid impeller arm means.

2. A pump comprising, in combination, impeller housing means having afront head portion thereof spaced from a rear head portion thereof andhaving side wall means defining together a pumping chamber, rotatableimpeller drive means extending into said pumping chamber, rotatable andrigid impeller means rotatably carried by said drive means within saidpumping chamber and having a central portion and having rigid impellerarm means extending outwardly from the axis of rotation of said drivemeans, said rigid impeller arm means having impelling surface meansextending laterally outwardly from the central portion of said impellermeans toward said side wall means and also extending from the adjacenthead portion toward said other head portion a substantial distance ascompared to the distance between the tWo head portions, cylindricalpivot means carried by said rigid impeller arm means, said pivot meansbeing spaced radially outwardly from said drive means and being parallelto the axis of rotation of said drive means and extending from saidrigid impeller arm means toward said front head portion of said housingmeans, and impeller vane means releasably pivoted to and pivotallycarried by said pivot means and extensible radially outwardlyintermediate said rigid impeller arm means and said front head portionof said housing means, said impeller vane means being rotatable in anorbit around the axis of rotation of said drive means and also being ofsuch length and of such construction and arrangement that the center ofgravity of said impeller vane means is at all times spacedcircumferentially from a flat plane including the axis of rotation ofsaid drive means and the axis of said pivot means, whereby when saidpump is in operation said impeller vane means is radially extended uponsaid pivot means by centrifugal force generated in said impeller vanemeans.

3. A centrifugal pump, comprising, in combination, housing means havingspaced front and rear head portions and side Wall means definingtogether a pumping chamber, a circular inlet aperture in one of saidhead portions, rotatable drive shaft means extending into said pumpingchamber and being axially aligned with said inlet aperture, a rotatableand rigid impeller element carried by said shaft means and having rigidimpeller arrn means extending radially outwardly from the axis ofrotation of said shaft means and having impelling surface meanscomprised of leading edge means of said arm means and extendinglaterally outwardly from the central portion of said impeller elementand also extending axially of said chamber intermediate said headportions a substantial distance as compared to the distance intermediatesaid head portions, pivot means carried by said rigid impeller arm meansintermediate said rigid impeller arm means and said head portion havingthe circular inlet aperture, the axis of said pivot means being parallelto the axis of said drive shaft means and being spaced radiallyoutwardly from said drive shaft means a distance substantially equal tothe radius of said inlet aperture, and impeller vane means pivotallysupported upon said pivot means for rotation in an orbit about saiddrive shaft means in a path parallel to and adjacent to the path ofrotation of said rigid impeller arm means.

4. A pump, comprising, in combination, housing means, rotatable impellerdrive shaft means extending into said housing means, a rotatable andrigid impeller element mounted on said drive shaft means Within saidhousing means, said rigid impeller element having a rigid impeller armmeans extending radially outwardly from said drive shaft means andhaving a leading fixed impelling surface means fixed with respect tosaid impeller arm means and extending laterally ontwar ly from thecentral portion of said peller element and also extending axially withrespect to said drive shaft means and being rotatable in a circularorbit in a path parallel to a surface of said housing means, pivot meanscarried by said rigid impeller arm means, said pivot means being spacedradially outwardly from said drive shaft means and parallel to saiddrive shaft means, and impeller vane means pivotally supported upon saidpivot means for rotation in an orbit about said drive shaft means in apath parallel to and adjacent to the path of rotation of said fixedimpelling surface means.

5. A pump, comprising, in combination, housing means having spaced frontand rear head portions and side Wall means defining to ther a pumpingchamber, an aperture in one of said head portions, rotatable drive shaftmeans extending into said pumping chamber through said aperture, arotatable and rigid impeller element positioned adjacent to andcompletely overlying said aperture and having rigid impeller arm meansextending radially outwardly from the axis of rotation of said shaftmeans and having a leading impelling surface means formed on the leadingedge of and fixed in position with respect to said arm means andextending laterally outwardly from the central portion of said impellerelement and also extending axially With respect to said drive shaftmeans a substantial distance compared to the distance intermediate saidhead portions and being rotatable in a path parallel to a surface ofsaid housing means, and impeller vane means carried by said impeller armmeans and pivoted thereon eccentrically of said drive shaft means forrotation in an orbit about said drive shaft means in a path parallel toand adjacent to the path of rotation of said rigid impeller arm means.

6. A pump, comprising, in combination, impeller housing means defining apumping chamber, rotatable impeller drive means extending into saidpumping chamber, rotatable and rigid impeller means carried by saiddrive means Within said pumping chamber and having a central portion andhaving rigid impeller arm means extending outwardly from the axis ofrotation of said drive means, said rigid impeller arm means having aleading edge comprising an impelling surface means extending axiallywith respect to said drive means Within said chamber and extendinglaterally outwardly from the central portion of said impeller means andin fixed position with respect to said impeller means, and impeller vanemeans pivotally carried by said rigid impeller arm means and extensibleradially outwardly from said drive means, said impeller vane means beingrotatable in an orbit around the axis of rotation of said drive meansand also being of such length and of such construction and arrangementthat the center of gravity of said impeller vane means when rotating insaid orbit is at all times spaced rear- Wardly with respect to itsdirection of rotation and circumferentially from a flat plane includingthe axis of rotation of said drive means and the axis of pivoting ofsaid impeller vane means on said rigid. impeller arm means.

7. A pump, comprising, in combination, housing means, rotatable impellerdrive shaft means extending into said housing means, a rotatable andrigid impeller element mounted on said drive shaft means Within saidhousing means, said rigid impeller element having rigid impeller armmeans extending radially outwardly from said drive shaft means and saidarm means having a leading edge comprising an impelling surface meansextending axially with respect to said shaft means within said housingmeans and extending laterally outwardly from the central portion of saidimpeller element and rotatable in a circular orbit in a path parallel toa surface of said housing means and in fixed posit-ion with respect tosaid arm means, and impeller vane means carried by said rigid impellerarm means and pivoted thereon eccentrically of said drive shaft meansfor rotation in an orbit about said drive shaft means in a path parallelto and adjacent to the path of rotation of said impelling surface means.

8. A centrifugal pump, comprising, in combination, a pump housing ofsubstantially cylindrical configuration and having a centrally aperturedfront head portion spaced from and parallel to a centrally aperturedrear head portion and also having a side wall portion, said front headportion and said rear head portion being substantially fiat andsubstantially circular, said side wall portion being substantiallycylindrical and coaxial with said front head portion and with said rearhead portion and forming therewith a substantially cylindrical pumpingchamber, annular seal means sealingly engaging adjacent surfaces of saidside Wall and said rear head portion, rotatable cylindrical drive shaftmeans axially aligned with the apertures in said front head portion andsaid rear head portion and extending into said pumping chamber throughthe aperture in said rear head portion, circular inlet meanscommunicating with and axially aligned ith the aperture in said fronthead portion, seal means for sealing the space intermediate said driveshaft means and the adjacent edge of the aperture in said rear headportion, rotatable and rigid impeller means releasably carried by saiddrive shaft means within said pumping chamber, said impeller meanshaving radially extending arm means provided with substantially fiat andparallel front and rear face surfaces which are perpendicular to theaxis of said drive shaft means and each of which faces is substantiallyof a configuration of an elongated rectangle having rounded ends, saidimpeller means also having a cylindrical central hub portion telescopedover and axially aligned with said drive shaft means and having one endof said hub portion extending through the aperture in said front headportion, said rigid impeller means being positioned adjacent to andcompletely overlying said aperture in said rear head portion and havingleading edge means comprising impel'ling surfaces extending laterallyoutwardly from the central portion of said rigid impeller means andpositioned intermediate said face surfaces, cylindrical pivot meanscarried by said rigid impeller means, said pivot means being spacedradially outwardly from and parallel to said drive shaft means andextending from said rigid impeller means toward said front head portionand having the axis of said pivot means spaced from the axis of saiddrive shaft means a distance substantially equal to the radius of theaperture in said front head portion, and impeller vane means releasablypivoted to and carried by said pivot means and extensible radiallyoutwardly intermediate said rigid impeller means and said from headportion, said impeller vane means being so constructed and arranged thatwhen rotating the center of gravity thereof is spaced rearward'ly withrespect to its direction of rotation and circumferentially from a flatplane including the axis of pivoting thereof and the axis of rotation ofsaid shaft means.

9. In combination, rotatable impeller drive shaft meas, rigid impellermeans rotatably carried by said shaft means, said impeller meansincluding a central portion and outwardly extending and opposed andrigid impeller arm means, said rigid impeller arm means having impellingsurface means extending outwardly toward the outer ends of said rigidimpeller arm means, and impeller vane means pivotally carried by saidrigid impeller arm means radially outwardly of said drive shaft androtatable in an orbit around the axis of rotation of said drive shaftmeans and extensible radially outwardly from the axis of pivoting ofsaid impeller vane means, said impeller vane means being so constructedand arranged that when rotating the center of gravity thereof is spacedrearwardly with respect to its direction of rotation andcircumferential-1y from a fiat plane including the axis of rotationthereof and the axis of rotation of said shaft means.

10. An impeller for a pump, comprising, in combination, a rotatable andelongated and rigid impeller element supported upon a rotary drive shaftand having rigid impeller arm means extending radially outwardly fromthe axis of rotation of said impeller element, the maximum dimension ofsaid impeller arm means taken lengthwise thereof being greater than themaximum dimension of said impeller arm means taken perpendicular to theline of said maximum lengthwise dimension thereof, said impeller armmeans having leading edges comprising impelling surface means extendinglaterally out avardly from the central portion of said impeller elementand positioned rearwardly of said impelling surface means with respectto the direction of rotation of said impeller element and impeller vanemeans carried by said rigid impeller arm means and pivoted thereon eccentrically of said drive shaft for said impeller element.

'11. An impeller for a pump, comprising, in combination, an elongatedand rigid rotatable impeller element supported upon a rotary drive shaftand having rigid impeller arm means extending radially outwardly fromthe axis of rotation of said impeller element, said arm means havingleading edge means comprising impelling surface means, and impeller vanemeans carried by said rigid impeller arm means and positioned rearwardlyof said impelling surface means witn respect to the direction ofrotation of said impeller element and pivoted thereon eccentrically ofsaid drive shaft for said impeller element.

7 12. In combination, a rigid impeller means supported upon a rotarydrive shaft and having a central portion .and having rigid impeller armmeans extending outwardly from said central portion, said impeller meansbeing adapted to be rotated about an axis of rotation extending throughsaid central portion, fixed impelling "surfaces on said rigid impellerarm means extending laterally outwardly from said central portion, andimpeller vane means pivotally carried by said rigid impeller ,arm meanson pivot means positioned radially outwardly of said shaft andextensible radially outwardly from the axis of rotation of said impellermeans upon the rotation of said impeller means, said impeller vane meansbeing rotatable in an orbit around the axis of rotation of said impellermeans and being of such construction and arrangement that the center ofgravity of said impeller vane means when rotating in such orbit is atall times spaced rearwardly with respect to its direction of rotationand circumferentially from said impelling surface and from a flat planeincluding the axis of rotation of said impeller means and the axis ofpivoting of said impeller vane means on said rigid impeller arm means.

13. In combination, a rigid blade means having a central portion andhaving impelling surfaces formed on the leading edges of opposed andrigid arm means extending laterally outwardly from said central portion,said blade means being adapted to be rotated about an axis of rotationof a drive shaft supporting said blade means and extending through saidcentral portion, and impeller vane means pivotally carried by saidopposed and rigid arm means upon pivot means positioned radiallyoutwardly of said shaft, said vane means being extensible radiallyoutwardly from the axis of rotation of said blade means, said impellervane means being rotatable in an orbit around the axis of rotation ofsaid blade means and being of such construction and arrangement that thecenter of gravity of said impeller vane means when rotating is spacedrearwardly with respect to its direction of rotation andcircumferentia'lly from said impelling surfaces and from a flat planeincluding the axis of rotation of said blade means and the axis ofpivoting of said impeller vane means on said rigid arm means.

14. In combination, housing means, drive shaft means extending into saidhousing means, impeller carrier means supported within said housingmeans by said drive shaft means, impeller vane means pivotally carriedupon said impeller carrier means by telescoped pivot means positionedeccentrically of the axis of said drive shaft means, said impellercarrier means being so positioned with respect to said housing means asto maintain said impeller vane means pivotally supported upon saidtelescoped pivot means, said pivot means comprising a cylindrical innermember telescoped into an outer member, one of said members having a keymeans engaged with a guide surface at least partially encircling theother member, said key means and said guide surface being so constructedand arranged as to lock together said inner member and said outer memberfor certain predetermined positions of relative rotation of said innermember with respect to said outer member and to permit axial movement ofsaid inner member with respect to said outer member in anotherpredetermined position of relative rotation of said inner member withrespect to said outer member.

15. An impeller for a pump, comprising, in combination, a rotatableimpeller element having rigid impeller arm means extending radiallyoutwardly from the axis of rotation of said impeller element, impellervane means carried by said rigid impeller arm means and pivoted thereoneccentrically of the axis of rotation of said impeller element, pivotmeans fixed to said rigid impeller arm means and pivotally carrying saidimpeller vane means for pivoting in a plane spaced from and parallel toand overlying the path of movement of said rigid impeller arm means,annular groove means in said pivot means, and key means carried by saidimpeller vane means and having an end thereof extending into said groovemeans for pivotally retaining said impeller vane means in pivotingposition upon said pivot means.

16. An impeller according to claim 15, having longitudinal groove meansextending longitudinally from one end of said pivot means into saidannular groove means, said longitudinal groove means and said annulargroove means being so constructed and arranged that when the end of saidkey means which extends into said annular groove means is aligned withsaid longitudinal groove '0 1:: means said impeller vane means may bemoved longitudinally with respect to the axis of said pivot means.

17. An impeller according to claim 16, wherein said key means is sopositioned in said impeller vane means and wherein said longitudinalgroove means is so positioned in said pivot means and wherein saidimpeller vane means is so constructed and arranged that upon therotation of said rotatable impeller element the centrifugal forcegenerated Within said impeller vane means will pivot said impeller vanemeans upon said pivot means into a position wherein said key means isspaced remotely from a position of alignment with said longitudinalgroove means.

8. In combination, rotatable carrier means, carried means pivotal lycarried upon said carrier means by telescoped pivot means, saidtelescoped pivot means pivotally carrying said carried means upon saidcarrier means and positioned eccentrically of the axis of rotation ofsaid carrier means, said telescoped pivot means comprising a cylindricalinner member telescoped into an outer member, one of said members havinga key means engaged With a guide surface at least partially encirclingthe other member, said key means and said guide surface being soconstructed and arranged as to lock together said inner member and saidouter member for certain predetermined positions of relative rotation ofsaid inner member with respect to said outer member and to permit axialmovement of said inner member with respect to said outer member inanother predetermined position of relative rotation of said inner memberwith respect to said outer member.

19. In combination, rotatable carrier means, carried means carried bysaid carrier means, pivot means fixed to said carrier means andpivotally carrying said carried means upon said carrier means, annulargroove means in said pivot means, and key means supported by saidcarried means and having an end of said key means extending into saidgroove means for pivotally retaining said carried means in pivotingposition upon said carrier means.

References Cited in the file of this patent UNITED STATES PATENTS1,074,794 Hunt Oct. 7, 1913 1,107,881 Berntsen et al Aug. 18, 19141,296,042 Bralove Mar. 4, 1919 1,297,995 Bralove Mar. 25, 1919 1,817,169Schwitzer et all. Aug. 4, 1931 2,291,797 Dalzell Aug. 4, 1942 2,500,914Sells et a1 Mar. 14, 1950 2,537,523 Frost Jan. 9, 1951 2,569,308 HaapalaSept. 25, 1951 2,784,673 Namur Mar. 12, 1957 2,798,438 Greathouse July9, 1957 2,841,946 Skromme et a1. July 8, 1958 2,856,806 Gibbons Oct. 21,1958 2,986,095 Namur May 30, 1961 FOREIGN PATENTS 302,953 Great BritainDec. 21, 1928 338,186 Germany June 14, 1921 1,092,549 France Nov. 10,1953

1. A CENTRIFUGAL PUMP, COMPRISING, IN COMBINATION, HOUSING MEANS HAVINGSPACED AND PARALLEL AND SUBSTANTIALLY FLAT FRONT AND REAR HEAD PORTIONSAND SUBSTANTIALLY CYLINDRICAL SIDE WALL MEANS DEFINING TOGETHER APUMPING CHAMBER, A CIRCULAR INLET APERTURE IN THE CENTER OF THE FRONTHEAD PORTION OF SAID HOUSING MEANS, A DRIVE SHAFT APERTURE IN THE CENTEROF THE REAR HEAD PORTION OF SAID HOUSING MEANS, A ROTATABLE DRIVE SHAFTEXTENDING THROUGH SAID DRIVE SHAFT APERTURE INTO SAID PUMPING CHAMBER,SEAL MEANS SEALING SAID DRIVE SHAFT APERTURE ABOUT SAID DRIVE SHAFT, ANELONGATED AND SUBSTANTIALLY RECTANGULAR AND ROTATABLE AND RIGID IMPELLERELEMENT CARRIED CENTRALLY THEREOF BY SAID DRIVE SHAFT WITHIN SAIDPUMPING CHAMBER AND HAVING OPPOSED RIGID IMPELLER ARM MEANS EXTENDINGRADIALLY OUTWARDLY FROM THE AXIS OF ROTATION OF SAID DRIVE SHAFT ANDINCLUDING INTEGRALLY FORMED IMPELLING SURFACE MEANS EXTENDING RADIALLYOUTWARDLY FROM THE CENTRAL PORTION OF SAID IMPELLER ELEMENT AND BEINGFORMED ON THE LEADING EDGES OF SAID IMPELLING ARM MEANS AND EXTENDINGSUBSTANTIALLY AXIALLY OF SAID CYLINDRICAL SIDE WALL MEANS AND DISPOSEDFOR ROTATION IN A PLANE PARALLEL TO THE PLANE OF THE REAR HEAD PORTIONOF SAID HOUSING MEANS, SAID RIGID IMPELLER ELEMENT BEING POSITIONEDADJACENT THE REAR HEAD OF SAID HOUSING MEANS AND COMPLETELY OVERLYINGSAID SEAL MEANS, SAID RIGID IMPELLER ARM MEANS HAVING A MAXIMUM RADIALDIMENSION GREATER THAN THE MAXIMUM DIMENSION OF SAID RIGID IMPELLER ARMMEANS TAKEN PERPENDICULAR TO THE LINE OF MAXIMUM RADIAL DIMENSION ANDHAVING PARALLEL AND FLAT MAJOR FRONT AND REAR SURFACES PARALLEL TO ANDSPACED FROM THE FRONT AND REAR HEAD PORTIONS OF SAID HOUSING MEANS, SAIDIMPELLING SURFACE MEANS BEING POSITIONED INTERMEDIATE AND JOINING SAIDFLAT MAJOR FRONT AND REAR SURFACES OF SAID RIGID IMPELLER ARM MEANS,PIVOT MEANS CARRIED BY SAID RIGID IMPELLER ARM MEANS INTERMEDIATE SAIDRIGID IMPELLER ARM MEANS AND THE HEAD PORTION OF SAID HOUSING HAVING THECIRCULAR INLET APERTURE, THE AXIS OF SAID PIVOT MEANS BEING PARALLEL TOTHE AXIS OF SAID DRIVE SHAFT AND BEING SPACED RADIALLY OUTWARDLY FROMSAID DRIVE SHAFT A DISTANCE SUBSTANTIALLY EQUAL TO THE RADIUS OF SAIDINLET APERTURE, AND IMPELLER VANE MEANS PIVOTALLY SUPPORTED UPON SAIDPIVOT MEANS FOR ROTATION IN AN ORBIT ABOUT SAID DRIVE SHAFT IN A PATHPARALLEL TO AND ADJACENT TO THE PATH OF ROTATION OF SAID RIGID IMPELLERARM MEANS.